1. Just Enough Unix, Chapter 1
Introduction to UNIX
Just Enough Unix, Chapter 1

2. What is UNIX? Operating system (OS), software
Widely used in industry, government, academia
Excellent OS for multiuser systems

3. Operating System Functions
Management of computer resources, such as memory, CPU, and I/O devices
Enables interaction with the user
Management of other software, scheduling

4. UNIX History
Began as a joint venture called Multics involving GE, MIT, and AT&T’s Bell Labs
Multics was too ambitious and by 1969 failed.
Ken Thompson and Dennis Ritchie, who had worked on Multics, wrote Unics (later called UNIX) for a minicomputer at Bell Labs.
In 1971 they wrote a UNIX-based word- processing system for the Bell Labs patent department. It was very successful.

5. UNIX History
Bell Labs could not, by law, compete in the computer industry so they gave UNIX away for free.
Computer Scientist at Universities introduced improvements.
Berkeley produced its own version
Many computer companies created their own versions.
CS computers use Sun’s Solaris
In 1991 Linus Torvalds created Linux, an OS similar to UNIX, for personal computers.

6. Open vs. Proprietary
Proprietary: Designed to work only on certain types of computer hardware.
MS-DOS (1980’s) ran only on machines with Intel CPU’s (Central Processing Unit)
Original Macintosh OS ran only on machines with Motorola CPU’s
Open: No single company developed or owns UNIX
Unix is portable - runs on a variety of hardware

7. The Four Main Components of UNIX
Kernel
Manages resources (memory, i/o devices, etc.)
File System
Organization of data
Shell
Interprets user commands and passes them to the kernel
Command-line interface
Utilities
Commands

8. The UNIX “Onion” File system File system File system File system
Utilities
Utilities
Utilities
Shell
Shell
Shell
Kernel
Kernel
Kernel
Hardware
Hardware
Hardware
Hardware
File system
File system
File system
File system

9. Hardware
Hardware is what determines what version, or type, of UNIX is installed.
Miller uses Solaris 8
Machine Hardware is i86pc
i386 Processor
Grid uses Solaris 9
Machine Hardware is Sun4u
Sun Sparc Processor

10. Kernel The kernel is the master control of the computer.
Controls resources and schedules users jobs
Programs interact with the kernel through system calls.

11. Shell Is the user - interface
Interpreter between the user and the kernel.
Takes commands from the user, decides if it is a valid command, then sends it to the kernel for processing.
Consistency across shells allows many version of UNIX to appear to be the same.

12. Utilities / Applications
The utilities are also known as the commands
such as pwd, ls, cat
Applications are software programs that allow users to solve specific problems.
Development tools
g++ , gcc complilers
Debuggers and archivers
Text Editors
Pico, Emacs, Vi
tools
Pine, Elm, Mail

13. File System How all the data is organized on the system.
The hierarchal file structure allows for organization of files into related groups
The similar structure across many different UNIX systems makes each system feel familiar to the user.